Dimmable ballast systems are employed for providing varying levels of light output. Conventional dimming ballasts include multiple discrete ballasts with one or more being selectively shut off to provide a lower light output. This approach, however, cannot achieve continuous dimming and is instead restricted to a finite number of discrete light output levels. This technique is further limited to multiple lamp installations. Conventional continuous dimming approaches operate lamps in series. This technique, however, can lead to premature lamp degradation or failure through undesirable lamp cooling and/or extinguishment. Moreover, this approach suffers from inability to produce light when one or more lamps fail. Another approach has been proposed in which a DC bus amplitude is varied via pulse width modulation (PWM) control to power a voltage or current fed inverter for driving one or more lamps, but this technique adds cost and has only proven feasible to about 10% of the rated lamp current, and thus does not provide the desired amount of dimming for certain applications. Thus, there is a continuing need for improved fluorescent lamp dimming apparatus and techniques for providing cost-effective varying light levels without lamp stress or damage.